1. Field of the Invention
The invention relates to an eddy current sensor and a sensor coil for such a sensor.
2. Description to the Related Art
An eddy current sensor comprises means for generating an eddy current in an electrically conducting test object and a sensor coil for the detection of the magnetic field of this eddy current. The sensor coil is part of a sensor circuit which produces an output signal indicating the distance between the sensor coil and the test object.
An already known type of eddy current sensor comprises a sensor head with a head portion of the sensor circuit including the sensor coil, a base unit with a base portion of the sensor circuit and a transmission cable connecting the head portion to the base portion of the circuit. Besides the sensor coil, most of the components of the sensor circuit are arranged in the base unit.
The accuracy of long term measurements with an eddy current sensor is adversely affected by the sensor's output signal drift.